Dropped by thrumbos after butchering, the thrumbo horn is a fairly powerful melee weapon which can be sold for a hefty amount of silver to Exotic Goods Traders.

Combat analysis

As a body part from a sacred thrumbo and its exceptional carbon properties, the thrumbo horn has a fairly good damage output and an exceptional market value. However, much like the elephant tusk; the thrumbo horn will generally be outclassed by many melee weapons, with the DPS of a thrumbo horn about the same as a Poor quality plasteellongsword, or between a Superior and Excellent quality steel longsword.

This means that the thrumbo horn should only really be used as weapon if you've got no other decent melee weapons in storage.